In the last 20 years, recording of single neurons has become one of the most common and successful approaches to understanding the operation of the nervous system. In the alert monkey, extracellular recording has revealed the eye movement related discharge patterns of oculomotor, reticular, and vestibular neurons, but not their afferent or efferent connections. On the other hand, in the anesthetized cat, intracellular recording has revealed the pattern of connections between, for example, vestibular and oculomotoneurons, but not their discharge patterns. This dichotomy has occurred because most anesthetics change the discharge patterns of brainstem neurons and suppress eye movements, thereby preventing behavioral correlations in most electrophysiological experiments. Recently however, this investigator in collaboration with others has shown that eye movement related discharge patterns of neurons are qualitatively similar in alert cats and in cats anesthetized with ketamine hydrochloride. Therefore, the major objective of this proposed study is to bridge the gap between previous intra- and extracellular studies of oculomotor function by studying the connectivity of behaviorally identified neurons in ketamine anesthetized cats. Correlation of structure and function is especially difficult in the reticular formation (RF). Single unit and lesion studies in alert monkeys suggest a prominent role for the RF in eye movements, but appropriate anatomical connections have been difficult to demonstrate. Therefore, this study will focus initially on the role of the reticular formation in eye movements by examining the connections between reticular neurons with eye movement related discharge patterns and oculomotoneurons.